Understanding the Kraus-Weber Test 1

The Kraus-Weber Abdominal Strength Test 1 assesses the strength of the abdominal and psoas muscles. Participants are required to perform one sit-up while keeping straight legs held raised off the ground. The test is part of the Kraus-Weber fitness test protocols, a series of six medical fitness tests measuring the strength and flexibility of key postural (core) muscles.

Originally developed by Dr. Hans Kraus and Dr. Sonja Weber in the 1950s, this test became nationally recognized after revealing that 58% of American children failed compared to only 9% of European children. This finding led directly to President Eisenhower establishing the President's Council on Physical Fitness and Sports.

How to Use This Calculator

Follow these simple steps to track your Kraus-Weber Test 1 performance:

  1. Perform the Test - Lie supine with hands behind head, legs straight, and have someone hold your feet. Attempt one complete sit-up.
  2. Record Your Result - Select whether you completed the full sit-up, achieved partial lift, or could not lift shoulders from the ground.
  3. View Your Assessment - See instant pass/fail determination with specific training protocols.
  4. Track Progress - Save results to monitor improvement over time within your session.

Pro Tip: Perform this test first thing in the morning before training for the most consistent results. The psoas muscles can become fatigued from running or jumping, affecting your ability to complete the sit-up later in the day.

Test Procedure and Technique

Test purpose: To assess the strength of the abdominal and psoas muscles, which are critical for core stability, athletic performance, and back pain prevention.

Equipment required: Flat surface (mat, floor, or grass), partner to hold feet

Pre-test: Explain the test procedures to the subject. Perform screening of health risks and obtain informed consent. Prepare forms and record basic information such as age, height, body weight, gender, test conditions. Ensure that the participants are adequately warmed-up. See more details of pre-test procedures.

Procedure: The subject lies down in supine position (flat on back) with hands clasped behind neck. The legs must remain straight throughout the test. The examiner holds the feet firmly to keep them on the ground. The subject attempts to perform one complete sit-up, rolling up from the shoulders until reaching a full seated position.

Scoring: This test is graded on a pass-fail basis. The subject passes if they can perform one complete sit-up with shoulders fully leaving the ground and reaching a seated position. The test is failed if the shoulders cannot be raised from the surface. The Kraus-Weber test comprises 6 exercises - being unable to perform even one of the six exercises results in failing the overall test.

Advantages: This is a very simple test to conduct, which can be performed quickly with minimal equipment. It provides clear pass/fail criteria and can be used with large groups simultaneously.

Comments: The difference between this test and the second Kraus-Weber Abdominal Strength Test is that in this case the legs are straight, so that the psoas muscles also play a significant part in the sit-up action. This makes Test 1 more challenging than Test 2.

Sport-Specific Applications

Strong abdominal and psoas muscles are essential across all athletic disciplines, but certain sports place particularly high demands on these muscle groups:

Collision Sports (Football, Rugby, Wrestling)

Athletes in collision sports require exceptional core strength for stability during contact, power transfer from lower to upper body, and injury prevention. The abdominals and psoas work together to maintain torso position during tackles, scrums, and grappling. Elite rugby forwards and NFL linemen typically pass this test easily, while inability to pass correlates with higher injury rates.

Gymnastics and Martial Arts

These disciplines demand the highest levels of core control. Gymnasts use psoas and abdominal strength for transitions between floor and apparatus movements, while martial artists need this strength for kicks, throws, and ground work. Olympic-level gymnasts not only pass this test but can perform multiple repetitions with added weight (5-10kg plates).

Endurance Sports (Running, Cycling, Triathlon)

While less obvious, endurance athletes need strong core muscles to maintain efficient posture over long durations. Weak abdominals and psoas lead to postural collapse in the late stages of races, reducing efficiency and increasing energy cost. Elite marathoners typically pass this test despite their lower absolute strength compared to power athletes.

Team Sports (Basketball, Soccer, Hockey)

These sports require rapid changes of direction, jumping, and rotational movements - all dependent on core strength. The psoas initiates hip flexion for sprinting and kicking, while the abdominals provide rotational stability. Professional soccer players who fail this test show reduced sprint performance and higher groin injury rates.

⚠️ Warning: If you experience sharp pain in the lower back or groin during this test, stop immediately and consult a sports medicine professional. Pain indicates potential injury or muscle imbalance that requires assessment before continuing training.

Scientific Background and Validation

According to sports science expert Robert Wood, who has analyzed sports performance data for over 25 years, the Kraus-Weber tests represent one of the earliest validated assessments of minimum muscular fitness. The original 1954 study by Kraus and Hirschland compared 4,400 American children with 3,000 European children, finding that American children had significantly higher failure rates across all six tests.

Research indicates that the psoas muscle plays a critical but often overlooked role in athletic performance. When performing the sit-up with straight legs (Test 1), the psoas must contract strongly to stabilize the pelvis and assist hip flexion. This combined action of abdominals and psoas is essential for explosive movements in sport.

Modern validation studies have confirmed the test's reliability, with inter-rater reliability coefficients exceeding 0.99 for experienced testers. The test successfully identifies individuals at higher risk for lower back pain, with failure rates correlating strongly with subsequent back problems in athletic populations.

Training to Improve Performance

If you fail this test, systematic training can lead to success within 4-8 weeks for most athletes. Research by Robert Wood shows that athletes who follow structured core training protocols pass the test on average after 5.2 weeks of consistent training.

Beginner Protocol (Weeks 1-2)

  • Bent-Knee Sit-Ups: 3 sets of 5 reps daily (easier variation to build foundation)
  • Dead Bug Exercise: 3 sets of 10 reps (develops abdominal control)
  • Plank Holds: 3 sets of 20-30 seconds (builds isometric strength)
  • Psoas March: Lying flat, raise one knee at a time - 3 sets of 10 per leg

Intermediate Protocol (Weeks 3-4)

  • Assisted Straight-Leg Sit-Ups: Partner provides minimal assistance at shoulders - 3 sets of 3 reps
  • Hollow Body Holds: 3 sets of 15-20 seconds (advanced abdominal work)
  • Leg Raises: 3 sets of 8 reps (strengthens lower abs and psoas)
  • Hanging Knee Raises: 3 sets of 5 reps if available (builds functional core strength)

Advanced Protocol (Weeks 5-6)

  • Unassisted Test Attempts: Attempt full test 2-3 times per week
  • Weighted Sit-Ups: Hold 2.5kg plate behind head for 3 sets of 5 reps
  • L-Sit Practice: Build up to 10-second holds (gymnastic core strength)
  • Sport-Specific Integration: Add rotational movements relevant to your sport

Athletic Integration Guidelines

  • Timing: Perform core work AFTER main training sessions, never before competition
  • Frequency: 5-6 days per week for fastest improvement; 3-4 days for maintenance
  • Volume: 15-20 minutes per session is sufficient; quality over quantity
  • Progression: Add 1-2 reps or 5 seconds per week to exercises
  • Rest: Take one full day off core work per week for recovery

Frequently Asked Questions

What does the Kraus-Weber Test 1 measure?

The Kraus-Weber Abdominal Strength Test 1 measures the combined strength of the abdominal muscles and psoas muscles. It assesses whether you have the minimum muscular fitness needed for core stability and postural support. This is different from Test 2, which isolates the abdominals by using bent knees.

How do I pass the Kraus-Weber Test 1?

To pass, you must perform one complete sit-up from a supine position with hands behind your head, legs straight, and feet held down. You must be able to raise your shoulders completely off the ground and sit all the way up to a full seated position. Simply lifting your shoulders slightly does not constitute a pass.

What if I can only do a partial sit-up?

A partial sit-up (lifting shoulders but not reaching full seated position) indicates you're on the right track but haven't yet achieved the minimum fitness standard. Continue with the beginner training protocol focusing on bent-knee sit-ups and assisted variations. Most athletes progress from partial to full within 2-3 weeks of consistent training.

Why is this test important for athletes?

Strong abdominal and psoas muscles are fundamental for athletic performance across all sports. They provide core stability for power transfer, maintain posture during fatigue, and prevent lower back injuries. Athletes who fail this test have been shown to have higher injury rates and reduced performance in explosive movements, sprinting, and rotational activities.

How often should I retest?

If you pass, retest every 4-6 weeks during training phases to ensure you maintain the minimum standard. If you fail, retest weekly while following the training protocol. Most athletes see measurable improvement within 2 weeks and achieve a pass within 4-6 weeks of consistent core training.

What's the difference between Kraus-Weber Test 1 and Test 2?

Test 1 uses straight legs throughout the movement, requiring both abdominal AND psoas strength. Test 2 uses bent knees, which minimizes psoas involvement and isolates the abdominals. Test 1 is typically harder because the psoas must work harder to stabilize the pelvis when legs are straight. Most athletes who fail Test 1 can pass Test 2.

Can I do this test at home?

Yes, this test is designed for easy home administration. You only need a flat surface and someone to hold your feet down firmly. Make sure the surface isn't slippery and you have adequate space. For the most accurate results, use the same location and time of day for all tests to ensure consistency in your progress tracking.

References

  1. Kraus, H., & Hirschland, R. P. (1954). "Minimum Muscular Fitness Tests in School Children." Research Quarterly, 25(2), 178-188.
  2. Kraus, H., & Weber, S. (1945). "Evaluation of Posture Based on Structural and Functional Measurements." Physiotherapy Review, 25, 267-271.
  3. Phillips, M., et al. (1955). "Analysis of Results from the Kraus-Weber Test of Minimum Muscular Fitness in Children." Research Quarterly American Association for Health, Physical Education and Recreation, 26(3), 314-323.
  4. Prudden, B. (1956). "Is Your Child Really Fit?" Sports Illustrated, August 1956.
  5. Gharote, M. L. (2000). "Study of Minimum Muscular Fitness in School Children Using Kraus-Weber Tests." Indian Journal of Physiology and Pharmacology, 44(4), 479-484.

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